Fuel pump



June 6, 1939. F. c. MOCK FUEL PUMP Filed Dec. 17, 1955 'INVENTOR. FrankC. Mock BY ZJMM ATTORNEY.

Patented June 6, 1939 FUEL PUMP Frank 0. Mock, Montclain, N. J.,'assignor to Eclipse Aviation. Corporation, East Orange, N. J., acorporation of New Jersey Application December 17, 1935, Serial No.54,894

2 Claims.

This invention relates to pumps, and more particularly to amulti-cylinder pump of the reciprocating piston type.

It has heretofore been proposed to provide v5 a multi-cylinder pumpwherein the cylinders have the longitudinal axes thereof disposedparallel and spaced about a common central axis which coincides with theaxis of rotation of a distributor adapted to control the discharge fromeach pump 10 cylinder. Such a pump has been used to supply fuel to thecylinders of internal combustion engines and is frequently referred toas a solid fuel injection pump. In the prior construction referred to,it has been considered necessary to provide means for bypassing aportion of the fuel discharged from each pump cylinder in order tocontrol. the quantity of fuel delivered to the engine cylinders.

An object of the present invention is to pro- 20 vide a novel pump ofthe above type of simplified construction and one which does not requirethe use of a variable or adjustable by-pass discharge opening in orderto regulate the rate of discharge from the pump.

Another object of the invention is to provide a multi-cylinder pumpembodying novel means for regulating the discharge from each pumpcylinder, said means constituting a distributor adapted to close theintake to each cylinder and 30 to open said intakes at selected times.

A further object is to provide novel pumping apparatus of the above typefor supplying fuel to an internal combustion engine, said apparatusbeing so constructed that each pump cylinder will 35 have a constantangular time of intake port opening for any given control setting, thetime in seconds of intake opening varying inversely as the engine speed.

Another object is to provide a novel method 4 for controlling the outputof a pump.

'A further object is to provide a novel pump of the typewherein'thepiston (or pistons) is of fixed stroke and is adapted to control theinlet to the pump cylinder, thevtime of inlet opening 45 being variablerelative to the position of said piston with-respect to the inlet,whereby the output of the pump is controlled. 7

A still further object is to provide a novel pump 50 for supplying fuelto the cylinders of an internal combustion engine, said pump being soconstructed. that the throttle lever or accelerator of the v .engine maybe employed to simultaneously control' the engine air supply valve andto regulate the 55 fuel discharge from saidpump to secure the desiredmixture of fuel and air supplied to the engine cylinders.

The above and other objects and advantages of the invention will appearmore fully hereinafter in the detailed description which is to be readwith the accompanying drawing illustrating the preferred embodiment. Itis to be expressly understood, however, that the drawing is for thepurpose of illustration only and is not designed as a definition of thelimits of the invention, reference being primarily had for this purposeto the appended claims.

In the drawing wherein like reference characters refer to like partsthroughout the several views, Fig. 1 is a longitudinal sectional viewillustrating a multi-cylinder pump constructed in accordance with theinvention;

Fig. 2 is a detail, partly in section and with parts broken away,illustrating suitable means for moving a pump piston to fuel dischargeposition in accordance with the present invention;

Fig. 3 is a detail, similar to Fig. 2, showing the piston and actuatingmeans therefor in discharge position; and

Fig. 4 is a diagrammatic view illustrating operating connections betweenthe pump shown in Fig. 1 and a multi-cylinder engine.

In the form shown in Fig. 1, the pump com prises a cup-shaped housing orcasing 5' provided in the inner wall thereof, adjacent the top, with anannular shoulder 6 which constitutes a support for a mounting ring I fora plurality of pump cylinders 8. Thimbles 9 threaded into ring 1 securesaid cylinders in operative position, the inner end of each thimblehaving engagement with a shoulder formed on theouter wall of thecylinder. A. piston ll) of fixed stroke, for each cylinder, is providedat its lower end with an adjustable tappet ll siidably guided in a platei2 rigidly mounted in any suitable manner, as by an annular shoulder, inthe lower portion of casing 5. Preferably, windows l3 are provided inthe casing to facilitate adjustment of-tappets I l, and said'windows maybe provided with a suitable closure or closures M. Acoilcompressionspring i5 is interposed between thimble 9 and a followerl6 rigidly attached in any suitable manner to the lower end'of thepiston, said spring surrounding an extension or sleeve 8a, formedintegrally with the wall of cylinder 8, which p rojects through thimble9 to provide the desired bearing surface 1 for the piston and tonreventengag'ement between the piston and'spring. The lattertendstomain- "tain' thepiston atthe end of its suction-stroke,

with follower I6 in engagement with the upper surface of plate I2.

Novel means are provided for moving pistons I8 to discharge position. Asshown, said means is constituted by a power or drive shaft I1 adapted tobe operatively connected in any suitable manner to a power shaft of theengine. Shaft I1 is rotatably mounted in casing by means of a hearing I8carried in the lower wall of the casing and a bearing I9 mounted in thecentral cupshaped portion I2a of member I2. The upper splined end I1a ofthe power shaft projects above the plane of the upper surface of memberI2. A radial arm 28 is rigidly attached to, or formed integrally with,shaft I1, intermediate the ends thereof, so that said arm projectslaterally between bearings I8 and I9. Mounted on the outer end of arm 28is a ball bearing cam roller 2I adapted to engage in succession thevarious piston tappets II whereby the pistons are moved to dischargeposition, said pistons being returned on the suction stroke by means ofsprings I5. It will be noted that the longitudinal axis of shaft I1coincides with the longitudinal axis of casing 5 and that the axes ofthe cylinders 8 are parallel thereto, the radial distance of eachcylinder axis from the shaft axis being the same.

Novel means are provided for distributing or supplying fuel to thevarious cylinders 8 through suitable cylinder intake passages 22, saiddistributor means being so constructed that the rate of fuel flow fromeach cylinder may be regulated by controlling said means. To this endcasing 5 is provided with a cover 23 having a centrally disposed passagein which is mounted a spacing sleeve 24. A threaded boss 23a. surroundsthe upper end of said passage to receive a nipple 25 for a fuel supplypipe 26 (Fig. 4). Cover 23 is provided on its lower face with a centraland inwardly extending sleeve 23b constituting a housing for a rotatabledistributor 21 adapted to be rotated by shaft I1 but angularlyadjustable relative to said shaft.

In the form illustrated, the lower end of distributor 21 is providedwith spiral splines 21a. which are engaged by a longitudinally movablesleeve 28, the lower end of said sleeve being slidably and drivablysecured to the upper end Hit of the power or drive shaft by means ofstraight splines. Preferably, the lower portion of distributor 21 is ofreduced diameter to provide a shoulder adapted to be engaged by suitablepacking and a gland 29 for retaining said distributor in operativeposition within sleeve 23b. The upper portion or head of thedistributor, which has a working clearance with the inner surface of thesleeve of approximately .002, is recessed to a diameter substantiallyequal to the inside diameter ofspacing sleeve 24, the fuel supplied tothe pump flowing through nipple 25, sleeve 24, and into said recess2117. A radial passage 38 is provided in the wall of the recessedportion or head of the distributor, said passage having a peripherysubstantially identical to that of a cross-section of each of thepassages 22 and being located longitudinally of distributor 21 so thatthere will be full registry between opening 38 and the adjacent ends ofeach of the passages 22 during rotation of the distributor.

It is desirable to provide for angular adjustment of distributor 21relative to intake passages 22 or cylinders 8, and for this purposesleeve 28 is provided with suitable collars 28a to receive a shiftingfork 3| adapted to be actuated by a rock shaft 32 which extends throughthe wall of easing 5. Movement of fork 3I in a counter-clockwisedirection, for example, moves sleeve 28 upwardly. whereby the angularposition of distributor 21 may be adjusted relative to the intakepassages 22 of the cylinders, and this adjustment is niade withoutdisturbing the driving relation'between said distributor and said shaft,and without longitudinal movement of the distributor.

Cover 23 is provided with discharge openings or passages 33 adapted tobe closed by one or more valves 34, 35. As illustrated, valve 34 is aspring pressed ball valve of less diameter than the spring pressed ballvalve 35. Seating spring 38 for ball valve 35 is positioned by the wallsof a recess formed in a nipple 31, threaded into a boss 38 on the cover,each of the nipples 31 receiving pipes, one of which is shown at 39 inFig. 4, for connecting each pump cylinder to the respective enginecylinder.

In operation, shaft I1 is rotated, whereby cam roller 2| engagesfollower levers II in succession .to actuate pistons I8 of fixed stroketo discharge fuel from cylinders 8 past valves 34, 35, pipes 39, to thecorresponding cylinders of the engine. After each piston or plunger I8is moved by roller 2I to discharge its fuel load, said piston is forceddownwardly or inwardly by spring I5, whereupon a partial vacuum iscreated in the cylinder above the piston. If the piston be moved byspring I5 to a position such that the upper end of the piston is belowintake passage'or side port 22, fuel will flow from the distributor intothe cylinder when distributor passage 38 registers with intake passage22. The amount of fuel drawn into the cylinder by the partial vacuum andhence the amount of fuel discharged from each cylinder may be regulatedby controlling the angular time said port 38 opens relative to theupward movement of piston I8, it being noted that in its upward movementthe piston is effective to seal the inner end of passage 22. The angularadjustment of distributor 21, and hence passage 38, is controlled bylongitudinal movement of sleeve 28.

It will be noted that the construction illustrated and described gives aconstant angular time of intake port opening, which results in anincreasing time in seconds of port opening as the engine speeddecreases. Consequently, an angular adjustment of distributor 21 isrequired which is similar to the angular adjustment required for theusual air intake or throttle valve of an internal combustion engine, andaccordingly the desired mixture ratio for the engine may be obtained bymechanically connecting the adjusting mechanism for the distributor tothe control lever for the engine air throttle.

As' shown more clearly in Fig. 4, the above connection may be effectedby means of a link 48 pivotally connected at one-end to an arm 4|secured to the rock shaft 32 for fork 3I. The opposite end of link 48 ispivotally connected to a bell crank lever 42 which is operatively mount-.ed on a fixed pivot that may be carried by the A throttle or air valve44 in said I pump which is simple in construction and which is adaptedfor a wide variety of uses. The pistons l coact with the angularlyadjustable distributor 21 to control the output of the pump. Forexample, if the distributor is adjusted to such an angular position thatport 30 does not begin to register with an inlet passage 22 until thepiston for said passage reaches a position, in its upward movement, suchthat the inner end of passage 22 is almost closed, it will be seen thatonly a small amount of fuel will be drawn into the cylinder, and hence asmall amount will be delivered to the engine cylinder. The time, inseconds, of intake opening varies inversely as the engine speed andaccordingly the adjusting means for the distributor may be mechanicallyconnected to the means for controlling the engine air intake valve.

Various changes may be made in details of construction and thearrangement of the parts, and, as will be understood by those skilled inthe art, the apparatus and the novel method disclosed are not limited touse in connection with fuel injection, nor tomulti-cylinder pumps. Itwill be understood that the term distributor as used here issufliciently broad to include means for controlling one or more inlets.Reference will accordingly be had, primarily, to the appended claims fora definition of the limits of the invention.

What is claimed is:

1. In a fluid pump, a body, a plurality of parallel cylinders thereinarranged about a central drive shaft, a piston in each of saidcylinders, a cam on said drive shaft arranged to actuate said pistons insequence, said cylinders having discharge ports and inwardly extendinginlet ports,

said pistons being movable to close said intake a portion forming ashaft, said valve shaft and said driving shaft being aligned, one ofsaid shafts having helical threads on its outer surface and the othershaft having straight splines, a slidable sleeve encircling the adjacentends of both shafts and cooperating with the threads and splines forchanging the angular relation between the shafts, means for preventingaxial movement of each of said shafts, said sleeve valve having'a portin its side wall adapted to align with each intake port in sequence, andmeans for introducing fiuid to the interior of said valve whereby thefluid is distributed to the cylinders.

2. In an apparatus of the class described, a casing, a fluid receivingdistributor rotatably mounted in said casing, means for preventing axialmovement of said distributor, a plurality of pump cylinders positionedin said casing at substantially equal radial distances from saiddistributor, said cylinders having intake-passages adapted to receivefluid from said distributor, said distributor being in the form of ashaft having an axial recess closed at its driven end and open at theother end for receiving a supply of fluid, and said distributor having aradial port extending through its side wall into said recess toperiodically align with the cylinder intake passages and to permit fluidto flow from the recess into the cylinders, pistons in said cylindersarranged to close the cylinder intake passages during reciprocation ofthe pistons, means including a shaft for actuating said pistons, saidshaft being axially aligned with said distributor shaft, means includingan axially movable sleeve encircling the adjacent ends of both shaftsfor angularly adjusting said distributor relative to said pistonactuating shaft and for driving the distributor.

FRANK C. MOCK.

